#multi-sync{
  margin-top: 10px;
  #doing{
    position: fixed;
    z-index: 10000;
    top:0;
    left:0;
    right:0;
    bottom: 0;
    background: rgba(0,0,0,0.7);
    color:#fff;
    font-size:16px;
    text-align: center;
    .box{
      position: absolute;
      width: 100%;
      top:50%;
      transform: translateY(-50%);
    }
  }
}